1. Technical Field
Embodiments of the present disclosure relate generally to delay line circuits, and more specifically to a delay locked loop with delay programmability.
2. Related Art
A delay locked loop (DLL) refers to a closed-loop feedback circuit that adjusts the phase of its output to achieve a desired phase difference between the output and an input signal. The adjustment is typically done based on an error signal generated as a comparison result of the phases of the output and the input signal. The input signal is typically a clock signal, a data stream or other periodic signal, while the output is typically a clock signal.
The phase difference between the output of a DLL and the input signal is termed as the ‘delay’ provided by the DLL. Delay programmability refers to a capability by which the delay provided by the DLL can be specified as an input value or otherwise be set in the DLL. The input specifying the delay may be provided, for example, as a “delay value” by an external device (e.g., by a processor external to the DLL). Alternatively, the desired delay may be obtained by activating one or more control signals provided as inputs to the DLL.